1. Field of the Invention
The present invention relates to a liquid discharge method and a liquid discharge apparatus for discharging a desired liquid by generation of bubble by thermal energy or the like and, more particularly, to a liquid discharge method and a liquid discharge apparatus using a movable separation film arranged to be displaced utilizing the generation of bubble.
It is noted here that "recording" in the present invention means not only provision of an image having meaning, such as characters or graphics, on a recorded medium, but also provision of an image having no meaning, such as patterns, on the medium.
2. Related Background Art
One of the conventionally known recording methods is an ink jet recording method for imparting energy of heat or the like to ink so as to cause a state change accompanied by a quick volume change of ink (generation of bubble), thereby discharging the ink through an discharge port by acting force based on this state change, and depositing the ink on a recorded medium, thereby forming an image, which is so called as a bubble jet recording method. A recording apparatus using this bubble jet recording method is normally provided, as disclosed in the bulletin of Japanese Patent Publication No. 61-59911 or in the bulletin of Japanese Patent Publication No. 61-59914, with an discharge port for discharging the ink, an ink flow path in communication with this discharge port, and a heat-generating member (an electrothermal transducer) as energy generating means for discharging the ink located in the ink flow path.
The above recording method permits high-quality images to be recorded at high speed and with low noise and in addition, because a head for carrying out this recording method can have discharge ports for discharging the ink as disposed in high density, it has many advantages; for example, high-resolution recorded images or even color images can be obtained readily by compact apparatus. Therefore, this bubble jet recording method is used in many office devices including printers, copiers, facsimile machines, and so on in recent years and further is becoming to be used for industrial systems such as textile printing apparatus.
On the other hand, the conventional bubble jet recording method sometimes experienced occurrence of deposits due to scorching of ink on the surface of the heat-generating member, because heating was repeated in a contact state of the heat-generating member with the ink. In the case of the liquid to be discharged being a liquid easy to deteriorate due to heat or a liquid not easy to generate a sufficient bubble, good discharge is not achieved in some cases by formation of bubble by direct heating with the aforementioned heat-generating member.
Against it, the present applicant proposed a method for discharging an discharge liquid by generating a bubble in a bubble-generating liquid by thermal energy through a flexible film for separating the bubble-generating liquid from the discharge liquid, in the bulletin of Japanese Laid-open Patent Application No. 55-81172. The configuration of the flexible film and the bubble-generating liquid in this method is such that the flexible film is formed in a part of nozzle, whereas the bulletin of Japanese Laid-open Patent Application No. 59-26270 discloses the configuration using a large film for separating the entire head into upper and lower spaces. This large film is provided for the purpose of being placed between two plates forming the liquid paths and thereby preventing the liquids in the two liquid paths from being mixed with each other.
On the other hand, countermeasures for giving a specific feature to the bubble-generating liquid itself and taking bubble-generating characteristics into consideration include the one disclosed in the bulletin of Japanese Laid-open Patent Application No. 5-229122 using a lower-boiling-point liquid than the boiling point of the discharge liquid, and the one disclosed in the bulletin of Japanese Laid-open Patent Application No. 4-329148 using a liquid having electric conductivity as the bubble-generating liquid.
However, the liquid discharge methods using the conventional separation film as described above are the structure of just separating the bubble-generating liquid from the discharge liquid or simply an improvement of the bubble-generating liquid itself, and they are not at the level of practical use yet.